/// <summary>
/// Creates and initializes a new instance of a complex lens.
/// </summary>
/// <param name="surfaces">List of element surfaces, ordered from
/// back to front.</param>
public ComplexLens(IList<ElementSurface> surfaces)
{
ElementSurfaces = surfaces;
ElementSurface frontSurface = surfaces.LastOrDefault((surface) => surface.Surface is Sphere);
frontSphericalSurface = (Sphere)frontSurface.Surface;
frontSurfaceSinTheta = frontSphericalSurface.GetCapElevationAngleSine(frontSurface.ApertureRadius);
frontSurfaceApertureRadius = frontSurface.ApertureRadius;
ElementSurface backSurface = surfaces.FirstOrDefault((surface) => surface.Surface is Sphere);
backSphericalSurface = (Sphere)backSurface.Surface;
backSurfaceSinTheta = backSphericalSurface.GetCapElevationAngleSine(backSurface.ApertureRadius);
backSurfaceApertureRadius = backSurface.ApertureRadius;
MediumRefractiveIndex = Materials.Fixed.AIR;
frontSurface.NextRefractiveIndex = MediumRefractiveIndex;
}
